carbon oxygenated residue modified L-tryptophan residue 2'-oxo-L-tryptophan 15.994915008544921875 16.0 202.0742340087890625 202.2100067138671875 C 11 H 10 N 2 O 2 2-azanyl-3-[(3S)-2-oxo-2,3-dihydro-1H-indol-3-yl]propanoic acid O 1 PSI-MOD A protein modification that effectively converts an L-tryptophan residue to a 2'-oxo-L-tryptophan. 2'-oxo-L-tryptophan 2-oxo-L-tryptophan none artifact MOD:01817 2-oxotryptophan W (2S)-2-amino-3-[(3S)-2-oxo-2,3-dihydro-1H-indol-3-yl]propanoic acid